1. Field of the Invention
This invention relates to domestic appliances.
2. Description of the Prior Art
The present invention is concerned with a domestic appliance having a heating apparatus comprising a heating element, a cable having a connection apparatus such as a plug at one end whereby the cable may be connected to a source of electrical power, normally a socket, and a connector apparatus for the heating apparatus capable of being connected to the other end of the cable. Such a domestic appliance is hereinafter referred to as an “appliance of the kind set forth”. The invention is particularly concerned with an appliance which is a water boiler such as a kettle or an urn.
The speed at which such an appliance or its contents can be heated is determined by the wattage of the power supply to the heating apparatus. This wattage is determined by the current capacity of the connection apparatus or the source of power, the latter of which is often controlled by a fuse or otherwise determined by the building regulations in various states. In many domestic arrangements the amperage is limited, for example, to 5 amperes. This in turn limits the power supply to the heating apparatus because the voltage of domestic power supplies is normally fixed. When the power supply voltage is low, such as 120 volts as in the United States and Canada, the power supply to the heating apparatus is relatively low, thereby causing the heating apparatus to heat slowly.
Solutions to this problem have been suggested in the patent literature. These solutions involve using an adapter which is arranged to draw power from a plurality of connection apparatuses and to increase the voltage of its output so that increased power is provided to the heating apparatus. Typical of such prior arrangements are those described in CA 2,289,821, U.S. Pat. No. 6,328,584; U.S. Pat. No. 5,160,852; and U.S. Pat. No. 5,936,828. Such solutions require the use of appliances produced for other markets which has limited the application of such arrangements.
Kettles have also been disclosed having a plurality of heater elements in WO 01/47399, JP 4046526 and JP 2003135274. In WO 01/47399 and JP 2003135274 the second heater element is provided to maintain the water temperature after it has boiled. In JP 4046526 one heater element is to be used when the power supply is low and another when the power supply is high. There is no indication that the two heater elements in any of these references are supplied with power from separate power supplies. None of these references deal with or attempt to show a solution to the problem facing the inventor as set forth above.